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Jens 16syncro
Joined: 09/16/2002 Posts: 469 Karma: +2 / -3
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27-07-2006, 10:20 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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Hi there,
I have a question that is currently still purely theoretical:
Can the software in the 1Z/AHU engine be reprogrammed to allow for a normal wastegate turbocharger without any boost control? A standard wastegate turbocharger regulates boost as well, but it's not influenced by the engine control unit (ECU). I believe that the 1Z/AHU engine doesn't have much regulation anyway, and it actually runs quite well even without any boost control.
If you do it like that, the engine control unit will probably constantly trigger a fault code related to the "intake manifold differential pressure."
Can the EGR valve and the mass airflow sensor be "reprogrammed" or disabled? Both seem to be unnecessary for the engine to run properly.
Wenn man ein solches umprogrammiertes AHU-Steuergerät hätte, würde das mit dem Motorkabelbaum vom AFN harmonieren ? IcI meant that.
Take the engine from an AFN car, remove the ECU from the AFN, install a modified one designed for an AHU, swap the turbo, and you're ready to go?
Regards,
Jens. Marcus "Ar Gwenn": Für uns sind Leute arm, weil sie mit einem Eselskarren unterwegs sind, für sie sind wir arm, weil wir ein Leben lang dafür arbeiten und Geld verdienen müssen, um uns im Alter von wildfremden Leuten pflegen zu lassen.
Translated on 21-07-2026, 12:24.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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27-07-2006, 10:33 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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"The 1Z/AHU engines already use a wastegate turbo, so no reprogramming is necessary."
The wastegates are very well regulated because a stock turbocharger only runs at 0.6 bar on its own. However, the engine control unit takes some pressure away from the wastegate actuator and can thus regulate up to 0.9 bar (which is the standard setting). The wastegate then opens later.
You can disable the AGR (Exhaust Gas Recirculation) by covering it with a metal plate and replace the MAF (Mass Air Flow) sensor with a diode. However, this can sometimes lead to noticeable black smoke coming from the exhaust, but that's just going out the back.
I don't know how well the wiring harness fits. In any case, the brackets and exhaust pipe do NOT fit.
Okay, please provide the German text you would like me to translate into English. I will only provide the translation. Transparency, Teamwork
... there was another T.
I don't know what the f*ck it was.
Translated on 21-07-2026, 12:27.
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Rudi Guest
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27-07-2006, 10:42 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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Hi Jens,
Radio Yerevan... in principle, most things should be possible, but what's the point?
In the turbocharger pressure control system, you would eliminate a valve that could potentially be a source of failure.
'These cost about 30 euros and lasted for approximately 300,000 kilometers in my car (which I would have used on a...'
Replace the expedition bus beforehand and take the old one as a spare.
AGR: It can be disabled in the software, but the mechanical lock is more secure.
LMM: Connect the diode directly to the control unit, and then nothing more can happen.
Best regards,
Rudi
[edit] Martin was faster [/edit]
[edit2] The wiring harness should fit. [/edit2]
Translated on 21-07-2026, 12:29.
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Jens 16syncro
Joined: 09/16/2002 Posts: 469 Karma: +2 / -3
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27-07-2006, 11:13 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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Rudi wrote: |
Radio Yerevan... in principle, most things should be possible, but what's the point?
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Hi Rudi,
Here's the translation:
"It's quite simple; I could use a turbocharger that I already have lying around. Besides, the 1Z turbo is already struggling with 1.1 bar of boost. I don't need the turbo's control system; I can't see any advantages in driving characteristics from a purely mechanical TDI engine that would be attributable to the control system. (As I said, this refers to the 1Z! It's not about the AFN)."
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AGR: It can be disabled in the software, but the mechanical lock is more secure.
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Currently, I have no more EGR system installed; the exhaust manifold has a blanking plate instead. Since you're already reprogramming things, you could also disable the EGR function in the software.
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LMM: Connect the diode directly to the control unit, and then nothing more can happen.
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Ah, directly into the control unit? I haven't seen that before. Is there a technical article about it?
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The wiring harness should fit | .
Very good! Does it matter if it's a 1Z or an AHU control unit?
Regards,
Jens. Marcus "Ar Gwenn": Für uns sind Leute arm, weil sie mit einem Eselskarren unterwegs sind, für sie sind wir arm, weil wir ein Leben lang dafür arbeiten und Geld verdienen müssen, um uns im Alter von wildfremden Leuten pflegen zu lassen.
Translated on 21-07-2026, 12:32.
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Jens 16syncro
Joined: 09/16/2002 Posts: 469 Karma: +2 / -3
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27-07-2006, 11:18 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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dieselmartin wrote: |
"Definitely, the catalytic converter and exhaust pipe do not fit."
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Hi Martin,
How do you mean that?
Of course, the manifold fits the cylinder head.
"The 1Z turbocharger doesn't fit the AFN manifold, I know that. However, I don't want to use either a 1Z or an AFN manifold; I want to use one from an SB engine with a matching turbo."
The exhaust needs to be replaced anyway, but it doesn't matter to me; it's not a problem.
Regards,
Jens. Marcus "Ar Gwenn": Für uns sind Leute arm, weil sie mit einem Eselskarren unterwegs sind, für sie sind wir arm, weil wir ein Leben lang dafür arbeiten und Geld verdienen müssen, um uns im Alter von wildfremden Leuten pflegen zu lassen.
Translated on 21-07-2026, 12:34.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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27-07-2006, 11:20 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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Okay, then we agree to meet at the Kruemmer  .
You can use any of the 1Z AHU ALE control units if one of them is compatible.
I'm driving one of the ALEs on the 1st.
As I said, a passive 1Z turbo produces 0.6 bar of pressure.
Roughly speaking, a (series) 1Z engine with 0.9 bar of boost produces 90 horsepower, so the 0.6 bar will likely bring about a hefty 60 horsepower (aside from any potential issues or error messages).
Then the T3 starts up really quickly (literally meaning "like the post office," because it takes forever).
Just put in the N75 knock sensor and that should fix it. I think I still have my old one lying around somewhere...
Okay, please provide the German text you would like me to translate into English. I will only provide the translation. Transparency, Teamwork
... there was another T.
I don't know what the f*ck it was.
Translated on 21-07-2026, 12:36.
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ulf Profi-Schrauber

Joined: 04/13/2002 Posts: 11058 Karma: +18 / -0 Location: Saarland 2023 MG ZS Premium Support
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27-07-2006, 11:32 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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dieselmartin wrote: | | Roughly speaking, a (series) 1Z engine with 0.9 bar of boost produces 90 horsepower, so 0.6 bar of boost will likely result in approximately 60 horsepower (excluding the turbocharger and any error entries). |
... and 0.0 bar therefore results in 0 horsepower - but why does a 1.9 naturally aspirated engine also have around 60 horsepower with 0 bar?
Tip: If you factor in an external pressure of 1 bar, the estimate will be slightly more accurate  .
Regarding the 1Z turbocharger... without digital control, shouldn't it still be possible to increase its boost by adjusting the length of the wastegate rod, like in the old days? Or is there a reason why that's not possible (even though things like thread lockers or coatings wouldn't be a valid reason for me)? Gruß Ulf
_________
MG4 Electric
Translated on 21-07-2026, 12:38.
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Rudi Guest
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27-07-2006, 11:35 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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You can use any of the 1Z AHU ALE control units if one of them fits.
I'm having one of the ALE beers on the 1st floor.
'1Z is compatible - if MSA15! The last series of MSA12 models can be replaced with MSA15.'
(Conversely, I would refuse to work on such a project using that software...)
MSA12 is already desecration  ).
There is no article about a diode in the transmission (getriebe).
It should be possible to configure the MSTG to work with an external LDR.
Best regards,
Rudi
Translated on 21-07-2026, 12:40.
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Jens 16syncro
Joined: 09/16/2002 Posts: 469 Karma: +2 / -3
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27-07-2006, 11:37 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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dieselmartin wrote: |
Roughly speaking, a (series) 1Z engine with 0.9 bar of boost produces 90 horsepower, so the 0.6 bar will likely bring about a hefty 60 horsepower (aside from any potential issues or error messages).
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Hello Martin,
I don't understand  .
I clearly stated that I wouldn't use a 1Z turbocharger. Therefore, it doesn't matter to me what boost pressure a 1Z turbocharger without regulation provides. I would install a Garrett TB0218 instead, which will likely achieve around 1.1 bar of boost.
Regards,
Jens. Marcus "Ar Gwenn": Für uns sind Leute arm, weil sie mit einem Eselskarren unterwegs sind, für sie sind wir arm, weil wir ein Leben lang dafür arbeiten und Geld verdienen müssen, um uns im Alter von wildfremden Leuten pflegen zu lassen.
Translated on 21-07-2026, 12:42.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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27-07-2006, 13:04 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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Hi Jens,
I had already typed out the answer when you replied faster.
That we agreed on the "Kruemmer" was an edit I made.
Okay, please provide the German text you would like me to translate into English. I will only provide the translation. Transparency, Teamwork
... there was another T.
I don't know what the f*ck it was.
Translated on 21-07-2026, 12:43.
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Nebelwerfer_TDI Guest
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27-07-2006, 16:39 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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LMM: Connect the diode directly to the control unit, and then nothing more can happen to you there.
Actually, it might also be possible to drastically increase the turbidity curve so that even a mass airflow sensor (MAF) that consistently reports only 200 mg/stroke doesn't reduce performance. What do you think?
AGR: It can be switched off in the software, but the mechanical lock is more secure.
So to speak, creating a level surface from the 'couch'?
'I bypassed the LD (likely referring to a specific tuning or regulation) on my car after figuring out what the tuner who provided my initial tune had done. It initially produced 0.6 bar of boost, increasing up to 0.7 bar under full load. Because he apparently also disabled the mass airflow sensor (MAF), the engine started running very poorly around 150 km/h. However, there were no error codes.'
Roughly speaking, a (series) 1Z engine with 0.9 bar of boost produces 90 horsepower, so the 0.6 bar will likely result in approximately 60 horsepower (excluding any potential issues or error messages).
Please remember that with the 90 horsepower at 0.9 bar (exactly 0.95), there is still plenty of excess air available, so even at 0.6 bar, you should still have around 75-80 horsepower. For comparison, the AAZ engine has a lower efficiency (because it's a chambered design) and produces 75 horsepower with 0.7 bar boost, without an intercooler.
Tip: When you factor in 1 bar of external pressure, the estimate becomes slightly more accurate.
Especially when you want to roughly calculate how much more air a boost pressure increase brings into the cylinders, and how much each turbocharger has to 'pump' in the case of the N-Max.
VAG COM displays the absolute pressure  not for fun.
By the way, apparently the front indicator light has different pin assignments on the STG 1Z and AHU models. You should try to find out exactly where that information is located; I'm not sure myself.
Translated on 21-07-2026, 12:46.
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Rudi Guest
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27-07-2006, 16:59 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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LMM: Connect the diode directly to the control unit, and then nothing more can happen to you there.
Actually, it should also be possible to drastically increase the opacity curve so that even a mass airflow sensor (MAF) that constantly reports only 200 mg/stroke doesn't reduce performance; what do you think?
It's a bit of both. On the one hand, there are more cooling fins to process the air mass; on the other hand, the mass airflow rate (MAF) is...
'In a Tromometer, there's one component more that can cause problems (which is why the diode is also included).'
ECU and not at the MAF sensor connector).
AGR: It can be switched off in the software, but the mechanical lock is more secure.
So to speak, turning the 'couch' into a plane.
or set the function switch for the EGR system accordingly.
By the way: apparently, the front indicator light has different pin assignments on the STG 1Z and AHU models. You should try to find out more about it; I'm not exactly sure where to look.
'Old 1Z, yes, but the MSA15 (.5) 1Z/AHU/AFN engines are actually very similar in terms of brake and clutch connections.'
'In some cases, the equipment configurations in Volkswagen vehicles differ from those in Audi vehicles, which may result in the cruise control system not functioning.'
- without engine revving - can be switched off using the clutch.
Best regards,
Rudi
Translated on 21-07-2026, 12:50.
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Nebelwerfer_TDI Guest
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27-07-2006, 17:03 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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or set the function switch for the EGR accordingly.
Aha  - if you can understand the program code yourself?!
so that the cruise control may not function in some cases.
- without engine revving - can be switched off using the clutch.
'However, mine also revs up to the limiter if I press the selector lever to 'N' while GRA is active. Could it be because the retrofit kit is intended for an AHU engine, but the ECU has the data set for an AFN engine?'
Translated on 21-07-2026, 12:53.
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Rudi Guest
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27-07-2006, 17:09 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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Mine also revs up to the limiter as well when I press the selector lever to 'N' while GRA is active. Could it be because the retrofit kit is intended for an AHU engine, but the ECU has the data set for an AFN engine?
 ... I am more afraid that shifting to 'N' while driving is not intended.
(and especially not when GRA is active)
Best regards,
Rudi
Translated on 21-07-2026, 12:55.
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Nebelwerfer_TDI Guest
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27-07-2006, 17:20 Subject: 1Z/AHU "simplified", control unit from AHU to AFN |
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... I'm more afraid that shifting to 'N' while driving is not intended.
(and definitely not when GRA is active).
I know that, but what should I do when curiosity beckons? 
Translated on 21-07-2026, 12:56.
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